[Paraneoplastic neurologic autoimmune diseases]

All complications of tumor disease that do not result from the tumor itself, its metastases, or vascular, infectious, metabolic, or therapy-related causes are referred to as paraneoplastic neurologic syndromes. This earlier represented an excluding diagnosis and the association was established only statistically, but since the first description of the anti-Hu antibody in 1985, we know that around 2/3 of patients with paraneoplastic disorders display highly specific antibody reactions in the serum. These reactions not only prove a paraneoplastic etiology in almost 100% of cases, but, due to their highly specific associations with certain tumor types, also aid tumor detection in patients whose tumor types are not known.

Tumor progression and serum anti-HuD antibody concentration in patients with paraneoplastic neurological syndromes

The aim of this study was to investigate whether there are clues for a correlation between tumor progression and serum anti-Hu antibody concentration in patients with anti-Hu-associated paraneoplastic neurological syndromes (PNS). 19 patients with anti-Hu-associated PNS were assigned to three groups according to the course of tumor progression. Group 1 corresponds to patients with rapid tumor progression [n = 5; mean survival in months/standard deviation (SD); 24/10]; in group 2 patients with a favorable tumor prognosis were included (n = 7; mean/SD 79/25, 6 patients still alive); group 3 consisted of patients in whom tumor progression could not be assessed (n = 7; mean/SD 23/20). The anti-Hu antibody concentrations in sera were measured in a recombinant HuD-ELISA. In sera from patients of group 1 the anti-Hu antibody concentration was modest (mean OD 0.56, SD 0.08) whereas a significantly higher anti-Hu antibody concentration was detected in sera from patients with a favorable tumor prognosis (group 2, mean OD 1.86, SD 0.34). These results hint at a negative correlation between tumor progression and the anti-Hu antibody concentration in sera from patients with PNS. These findings confirm and extend previous reports of more indolent tumor growth in patients with an anti-Hu immune response.

Disturbance in the serum IgG subclass distribution in patients with anti-Hu positive paraneoplastic neurological syndromes

Autoantibodies in patients with paraneoplastic neurological syndromes (PNS) have been reported to be predominantly IgG1 and IgG3 isotypes. However, no data are available about the IgG subclass distribution of the total serum IgG in these patients. Therefore, we investigated the IgG subclass distribution (given as percentage of total IgG) in 15 anti-Hu positive PNS patients, 15 patients with small cell lung cancer (SCLC) without PNS and 23 healthy controls using a commercial enzyme-linked immunosorbant assay test. Although IgG1 (and to a lower extent IgG3) are the predominant subclasses of the anti-Hu antibodies, PNS and SCLC showed a significant decrease in IgG1 and a concomitant increase in IgG2 compared with healthy controls (P < 0.05, respectively). In contrast, only SCLC patients, but not PNS patients, had higher IgG3 and IgG4 values compared with controls (P < 0.05, respectively). There was no correlation between IgG subclass levels and the titre or the predominant isotype of the antineuronal antibodies. PNS patients with autonomic disturbances had lower IgG4 levels than PNS patients without autonomic disturbances (P < 0.05). Our study demonstrates a disturbance in the IgG subclass distribution in PNS patients which is partly different from SCLC patients. The isotype regulation of the anti-Hu antibody seems to be independent from this phenomenon.

[Cloning, expression and purification of neural specific HuD cDNA]

OBJECTIVE

To prokaryoticly express and purify HuD protein and its RNA recognition motifs.

METHODS

HuD protein was prokaryoticly expressed and purified by molecular cloning technology. Its biologic activity was testified by Western Blot.

RESULTS

Purified HuD protein and its RNA recognized motifs were observed.

CONCLUSIONS

The result might aid for basic research and clinical application.

The immunopathogenesis of paraneoplastic neurological syndromes

Paraneoplastic neurological syndromes are rare non-metastatic complications of cancer that have an immune-mediated aetiology. The central and peripheral nervous systems are considered to be immune-privileged sites, since the presence of the 'blood-brain/nerve barrier' means that antigens sequestered within the nervous system do not normally induce an immune response. Aberrant expression of a neuronal antigen by a tumour arising outside this barrier can lead to the breakdown of immune tolerance to the nervous system. However, in many cases the immune mechanisms that result in neurological dysfunction remain poorly defined. Furthermore, aberrant expression of neuronal antigens can be detected in many tumours that are not complicated by non-metastatic neurological syndromes. This review article examines current concepts in the immunopathogenesis of paraneoplastic neurological syndromes.

Immunohistochemical analysis of anti-Hu-associated paraneoplastic encephalomyelitis

The precise immune mechanisms of neuronal death in anti-Hu-associated paraneoplastic encephalomyelitis (PEM) are unclear. We performed an immunohistochemical study on postmortem brain tissue from 11 patients with anti-Hu-associated PEM to further characterize the immune reaction and to ascertain possible mechanisms of neuronal death. To analyze inflammatory infiltrates, antibodies against lymphocyte subpopulations (CD3, CD20, CD4, CD8), macrophage and activated microglia (CD68), major histocompatibility complex (MHC) classes I and II (HLA-ABC and HLA-DR), and the intercellular adhesion molecules (ICAM) -1 and -3 were used. Cell death mechanisms were defined using antibodies against the cytotoxic protein TIA-1, the C9neo component of complement, the Fas receptor (CD95) and its ligand, the apoptosis effector activated caspase-3, and the apoptosis inhibitor Bcl-2. A great number of T cells expressing the cytotoxic protein TIA-1 was observed, mainly in clusters around neurons. ICAM-1 immunoreactivity was increased in the neuropil and reactive astrocytes in areas of inflammation within the central nervous system and in satellite cells of pathological dorsal root ganglia surrounding apparently normal sensory neurons. By contrast, Fas, FasL, C9neo, and activated caspase-3 immunoreactivities were negative in pathological areas. Bcl-2 immunoreactivity was found in satellite cells, but not in sensory neurons of normal and pathological dorsal root ganglia. Our data point out to an induction of a cytotoxic, non-apoptotic, neuronal death in anti-Hu-associated PEM. The increased ICAM-1 immunoreactivity may favor the infiltration of lymphocytes in the pathological areas.

Immunotherapeutic approaches to paraneoplastic neurological disorders

The review presents an overview on the pathogenesis of paraneoplastic neurological disorders (PNDs) and the current therapeutic immunosuppressive or immunomodulatory strategies used in these patients. PNDs are disturbances in the functioning of the nervous system in cancer patients, where the disturbances are not due to a local effect of the tumour or its metastases. Most of these clinically, well-defined syndromes in adults are associated with lung cancer (especially small cell lung cancer), lymphomas and gynaecological tumours. Since autoantibodies directed against proteins expressed in neurons and tumour cells have been found, PNDs are suspected to be autoimmune. In neuromuscular PND, immunosuppressive therapies, plasmapheresis and intravenous immunoglobulins are effective treatments. In contrast, central nervous system PNDs seen in adults are by far the most problematic group to treat. With exception of the stiff-man syndrome, immunosuppression appears to have little effect on these neurological disorders. Tumour therapy stabilises PNDs but does not cause improvement. Plasmapheresis reduces the autoantibody titre in the sera of these patients but, like tumour therapy, does not lead to a clinical improvement. In children with paraneoplastic opsoclonus-myoclonus syndrome, steroids and intravenous immunoglobulins may lead to a complete or partial remission of PNDs.

Quantification of circulating anti-Hu antibody in serial samples from patients with paraneoplastic neurological syndromes: possible correlation of antibody concentration and course of neurological symptoms

Serial samples, spanning an observation period of 4 to 10 years, from five patients with anti-Hu associated paraneoplastic neurological syndromes (PNS) were investigated with an enzyme linked immunosorbent assay (ELISA) employing recombinant HuD protein as antigen. In one patient the anti-Hu antibody concentration converted from negative to highly positive levels after the onset of neurological symptoms. These findings argue in favour of the idea that an autoimmune process, which is generated at the beginning of the neurological disease, causes the anti-Hu associated PNS. Serum samples obtained shortly after the beginning of the PNS were available from two other patients. The anti-Hu antibody levels in these latter patients increased from modest to highly positive anti-Hu antibody in follow up samples. In two patients a clear decrease of the anti-HuD antibody concentration together with an improvement of paraneoplastic neurological symptoms after successful tumour treatment were seen. Overall these data suggest that there might be a correlation between the anti-HuD antibody level and the clinical course of paraneoplastic neurological symptoms which supports further the hypothesis that an autoimmune process is responsible for the anti-Hu associated paraneoplastic neurological symptoms.

Molecular cloning and characterization of human PTB-like protein: a possible retinal autoantigen of cancer-associated retinopathy

Human homologue of polypyrimidine tract binding protein (PTB), a possible autoantigen for cancer-associated retinopathy (CAR), was isolated from a human retinal cDNA library. This homologue, named PTB-like protein (PTBLP), encodes a 532 amino acid residue and has a 75% homology to the human PTB. The human PTBLP had four RNA recognition motifs (RRMs) and had a RNA binding ability. There are four splicing variants in PTBLP. The CAR serum recognized the full length form of PTBLP and the antigenic determinant was localized within 12 amino acids of the C-terminal region. The sequence was included in the fourth RRM sequence.

Molecular and clinical diversity in paraneoplastic immunity to Ma proteins

Antibodies to Ma1 and Ma2 proteins identify a paraneoplastic disorder that affects the limbic system, brain stem, and cerebellum. Preliminary studies suggested the existence of other Ma proteins and different patterns of immune response associated with distinct neurologic symptoms and cancers. In this study, our aim was to isolate the full-length sequence of Ma2 and new family members, identify the major autoantigen of the disorder, and extend the dinical-immunological analysis to 29 patients. Sera from selected patients were used to probe a brainstem cDNA library and isolate the entire Ma2 gene and a new family member, Ma3. Ma3 mRNA is ubiquitously expressed in brain, testis, and several systemic tissues. The variable cellular expression of Ma proteins and analysis of protein motifs suggest that these proteins play roles in the biogenesis of mRNA. Immunoblot studies identify Ma2 as the major autoantigen with unique epitopes recognized by all patients' sera. Eighteen patients had antibodies limited to Ma2: they developed limbic, hypothalamic, and brainstem encephalitis, and 78% had germ-cell tumors of the testis. Eleven patients had antibodies to Ma2 and additional antibodies to Ma1 and/or Ma3; they usually developed additional cerebellar symptoms and more intense brainstem dysfunction, and 82% of these patients had tumors other than germ-cell neoplasms. Overall, 17 of 24 patients (71%) with brain magnetic resonance imaging studies had abnormalities within or outside the temporal lobes, some as contrast-enhancing nodular lesions. A remarkable finding of immunity to Ma proteins is that neurologic symptoms may improve or resolve. This improvement segregated to a group of patients with antibodies limited to Ma2.

ANNA-3 anti-neuronal nuclear antibody: marker of lung cancer-related autoimmunity

Two anti-neuronal nuclear antibodies (ANNA-1 and ANNA-2) are markers of paraneoplastic neurological autoimmunity related to small-cell carcinoma. ANNA-2 is also related to breast carcinoma. Here we define a third IgG specificity (ANNA-3), identified in 11 patients (10 adults) by immunofluorescence screening of sera from approximately 68,000 patients with suspected paraneoplastic neurological syndromes. ANNA-3 binds prominently to nuclei of cerebellar Purkinje neurons, not to cytoplasm, granular neurons, or enteric neurons, but distinctively to renal glomerular podocytes. Western blots revealed an approximately 170 kDa antigen, in cerebellum and small-cell carcinoma. IgG eluted from this protein reproduced Purkinje and podocyte nuclear staining. ANNA-2 in 8 of 32 cases bound to podocyte nuclei but not to the 170 kDa protein. Healthy subjects and control neurological and cancer patients lack ANNA-3. Neurological accompaniments, subacute and usually multifocal, included sensory/sensorimotor neuropathies, cerebellar ataxia, myelopathy, brain stem and limbic encephalopathy. All of 9 adults followed had an intrathoracic neoplasm, seven biopsied within 7 months (five small-cell lung carcinomas and two adenocarcinomas, one lung, one esophagus) and two imaged, one early, the other 3 years later. Thus, immunohistochemical and Western blot criteria can now identify six IgG markers of neurological autoimmunity related to small-cell carcinoma, their frequency being ANNA-1 > collapsin response-mediator protein-5 > amphiphysin > Purkinje cell cytoplasmic antibody-2 = ANNA-2 = ANNA-3.

Anti-Hu-associated paraneoplastic encephalomyelitis: analysis of 200 patients

We reviewed 200 patients with paraneoplastic encephalomyelitis (PEM) and anti-Hu antibodies to show possible clinical differences with respect to previous series, and to identify patient, tumour and treatment-related characteristics associated with neurological disability and survival. The median age of the 200 patients was 63 years (range 28-82 years) and 75% were men. The predominant neurological syndromes were sensory neuropathy (54%), cerebellar ataxia (10%), limbic encephalitis (9%) and multifocal involvement (11%). Sensorimotor neuropathies with predominant motor involvement were observed in only 4% of the patients. Pathological or X-ray evidence of a tumour was obtained in 167 patients (83%) and was a small-cell lung cancer (SCLC) in 74% of those with histological diagnosis. Coexistence of extrathoracic tumours with SCLC was rare (0.5%). Positive Hu immunoreactivity was observed in the extrathoracic tumours of six out of seven patients in whom autopsy or long-term follow-up ruled out a coexisting SCLC. PEM preceded the diagnosis of the tumour in 71% of patients (mean delay +/- SD 6.5 +/- 7.0 months; range 0.1-47 months). In the 24 patients in whom the tumour diagnosis was the initial event, PEM predicted the progression or relapse of the tumour in 87% of them. No tumour was found in 33 patients, including four who had a post-mortem study and four with >5 years of follow-up. In a logistic regression analysis, treatment of the tumour, associated or not with immunotherapy, was an independent predictor of improvement/stabilization of PEM [odds ratio 4.56; 95% confidence interval (CI) 1.62-12.86]. Cox multivariate analysis indicated that the variables independently associated with mortality were: age >60 years [relative risk (RR) 1.49; 95% CI 1.05-2.12], Rankin score at diagnosis >3 (RR 1.60; 95% CI 1.12-2.28), more than one area of the nervous system affected (RR 1.61; 95% CI 1.08-2.40), and absence of treatment (RR 2.56; 95% CI 1.76-3.71). We conclude that, unlike previous series, the majority of our patients were male, and there was a low occurrence of predominantly motor neuropathies and extrathoracic tumours coexisting with SCLC. When the diagnosed extrathoracic tumour expresses Hu antigens, further tests to rule out a coexisting SCLC are probably unnecessary. Finally, the predictors of mortality and PEM evolution found in the study may be important in the design of future therapeutic protocols, and emphasize the importance of early diagnosis and treatment of the underlying tumour.

Opsoclonus-myoclonus-ataxia syndrome in neuroblastoma: histopathologic features-a report from the Children's Cancer Group

BACKGROUND

Opsoclonus-myoclonus-ataxia (OMA) is a paraneoplastic syndrome that occurs in about 2-3% of all cases of neuroblastoma. The histopathologic characteristics of neuroblastoma tumors associated with this syndrome were evaluated in a series of cases and controls.

PROCEDURE

Pathology slides from a total of 54 neuroblastoma tumors were reviewed blindly. They included 13 tumors associated with opsoclonus-myoclonus and 41 age- and stage-matched controls. All tumors were classified into either the favorable (FH) or unfavorable histology (UH) group according to the International Neuroblastoma Pathology Classification (the Shimada system). Grade of lymphocytic infiltration was evaluated and presence or absence of lymphoid follicles was recorded in the individual tumor tissues.

RESULTS

Twelve of 13 cases with opsoclonus-myoclonus were in the FH group. Twelve of 13 cases had diffuse (found in every section prepared from the multiple portions of the primary tumor) and extensive (occupying more than 50% of a single of multiple microscopic fields with x 100 magnification) lymphocytic infiltration with lymphoid follicles. Of the 41 control cases (27 FH and 14 UH tumors), 18 had focal areas of lymphocytic infiltration and six showed lymphoid follicles, but none had diffuse or extensive infiltration in their primary tumors.

CONCLUSIONS

Diffuse and extensive lymphocytic infiltration with lymphoid follicles is a characteristic histologic feature of neuroblastic tumors with opsoclonus-myoclonus. This observation suggests an immune-mediated mechanism for this rare paraneoplastic syndrome.

Opsoclonus-myoclonus-ataxia syndrome in neuroblastoma: clinical outcome and antineuronal antibodies-a report from the Children's Cancer Group Study

BACKGROUND

Opsoclonus-myoclonus-ataxia (OMA) is a paraneoplastic neurologic syndrome affecting 2-3% of children with neuroblastoma. Although children with OMA and neuroblastoma may have higher survival, many experience a significant amount of late neurologic impairment, which may be immunologically mediated. The aim of this study was to compare the outcome of neuroblastoma patients with and without OMA, relating to prognostic factors, treatment, and the presence or absence of anti-neuronal antibodies.

PROCEDURE

Questionnaires were mailed out requesting information on the current neurologic status of patients who submitted sera at diagnosis to the Children's Cancer Group serum bank from 1980 to 1994. Information was requested on clinical and biological patient characteristics as well as clinical aspects of the patients identified as having OMA syndrome, including presentation and treatment for OMA, late sequelae of OMA, the presence or absence of antineuronal antibodies, and survival. Sera from 16 of the OMA patients and 48 case-controls with neuroblastoma were assayed for anti-neuronal antibodies.

RESULTS

Of the 675 responses received, 21 patients had OMA. Ninety percent of OMA patients presented with non-metastatic disease, vs. 35% of non-OMA patients. Estimated 3-year survival for the OMA patients with nonmetastatic disease (stage I, II, III) greater than 1 year of age was 100% vs. 77% for similar non-OMA patients (P = 0.0222). At follow-up, 14/19 evaluable OMA patients displayed some form of developmental or neurologic abnormality. There was no significant correlation of late sequelae with antineuronal antibodies, age, time between OMA symptoms and diagnosis, or treatment given for tumor or OMA. There was a significant correlation of late sequelae with lower stage disease (I and II) compared to more advanced disease (III and IV).

CONCLUSIONS

Patients with OMA and neuroblastoma have excellent survival but a high risk of neurologic sequelae. Favorable disease stage correlates with a higher risk for development of neurologic sequelae. The role of anti-neuronal antibodies in late sequelae of OMA needs further clarification.

Phenotypic and neuropathologic heterogeneity of anti-Hu antibody-related paraneoplastic syndrome presenting with progressive dysautonomia: report of two cases

The anti-Hu antibody (HuAb) is directed against RNA-associated neuronal proteins and is known to cause paraneoplastic encephalomyelitis/sensory neuronopathy syndrome mostly when associated with small cell lung cancer (SCLC). Paraneoplastic encephalomyelitis/sensory neuronopathy syndrome with concurrent autonomic neuropathy has been reported to occur in paraneoplastic syndromes, although its occurrence concomitant with acute pandysautonomia is less frequent. The authors describe the clinical, neuropathologic, and serologic features of two cases with an anti-Hu-related paraneoplastic syndrome presenting with progressive autonomic neuropathy. Both patients showed features of dysautonomia, including postural dizziness, abdominal pain, and diarrhea, and symptoms of sensory neuropathy. Investigations disclosed severe sensory and autonomic neuropathy and positive HuAb titers. The disease of patient 1 had a very rapid progression, and the patient died of cardiac arrest within 2 months of the onset of symptoms. The autopsy revealed SCLC. In contrast, the disease of patient 2 had a less aggressive course. An extensive tumor search disclosed SCLC only 28 months after onset of symptoms, and the patient died 1 month later of cardiorespiratory arrest. Autopsies in both cases showed inflammation involving the intermediolateral columns and the dorsal root ganglia. These two cases illustrate the association of early dysautonomia with HuAb-related paraneoplastic syndrome and the variations of clinical, neuropathologic, and serologic findings in these types of cases.

Antibody types and IgG subclasses in paraneoplastic neurological syndromes

Three major patterns of antineuronal antibody response have been identified in patients with paraneoplastic neurological syndromes: Type I ('Anti-Yo'), associated with cerebellar degeneration in the setting of breast or gynecological cancer, Type IIa ('anti-Hu') associated with encephalomyeloneuritis in patients with small cell carcinoma of the lung, and Type IIb ('anti-Ri') associated with breast cancer. We have employed immunofluorescence methods to determine the antibody classes and the IgG subclasses which react with neurons in each of these patterns of paraneoplastic antibody response. In this study, IgG was the only antibody class identified; IgM and IgA antibodies were not found. IgG1 was the major subclass represented and was found in 9/9 patients with Type I antibody response, 26/27 patients with Type IIa antibody response, and 3/3 patients with Type IIb antibody response. Many patients also exhibited positive staining for IgG2 and IgG3. Trace amounts of IgG4 antineuronal antibodies were detected in a single patient with Type I antibody response; IgG4 antibodies were not found in other patients. Patients with paraneoplastic neurological syndromes exhibit an antibody response which is overwhelmingly IgG and is comprised predominantly of IgG subclasses capable of fixing complement. The role of these antibodies in the pathogenesis of paraneoplastic neurological disease remains uncertain.

Paraneoplastic syndrome in the course of lung adenocarcinoma: morphological picture and immunohistochemical analysis of the inflammatory infiltrates and PECAM-1 expression

We examined sections of brain, spinal cord, spinal roots, and peripheral nerves from a patient with paraneoplastic syndrome in the course of lung adenocarcinoma. Morphological examination showed marked loss of myelin fibers in peripheral nerves, severe brain tissue edema, and paraneoplastic degeneration involving cerebrum and cerebellum with inflammatory components. Inflammatory infiltrates examined immunohistochemically using antibodies against antigens CD 3, CD 4, CD 8, and CD 20 turned out to be composed of cytotoxic T lymphocytes. The expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) in blood vessels was increased in comparison with control material, which may facilitate transendothelial lymphocyte migration triggering a cascade of biochemical and morphological reactions observed in paraneoplastic syndrome.

Paraneoplastic brain stem encephalitis in a woman with anti-Ma2 antibody

A woman developed brain stem encephalopathy in association with serum anti-Ma2 antibodies and left upper lobe lung mass. T2 weighted MRI of the brain showed abnormalities involving the pons, left middle and superior cerebellar peduncles, and bilateral basal ganglia. Immunohistochemical analysis for serum antineuronal antibodies was confounded by the presence of a non-neuronal specific antinuclear antibody. Immunoblot studies showed the presence of anti-Ma2 antibodies. A premortem tissue diagnosis of the lung mass could not be established despite two CT guided needle biopsies, and the patient died as a result of rapid neurological deterioration. The necropsy showed that the lung lesion was an adenocarcinoma which expressed Ma2 immunoreactive protein. Neuropathological findings included prominent perivascular inflammatory infiltrates, glial nodules, and neuronophagia involving the brain stem, basal ganglia, hippocampus and the dentate nucleus of the cerebellum. Ma2 is an autoantigen previously identified in patients with germ cell tumours of the testis and paraneoplastic brain stem and limbic encephalitis. Our patient's clinical and immunopathological findings indicate that this disorder can affect women with lung adenocarcinoma, and that the encephalitic changes predominate in those regions of the brain known to express high concentrations of Ma proteins.